Electric lamp connecting device



Maly 30,1939. J. BUSER ELECTRIC LAMP CONNECTING DEVICE Original Filed Feb. 1, 1938 Patented May 30, 1939 UNITED STATES ATENT OFFiCE' ELECTRIC LAMP CCNNECTING DEVICE Johann Buser, Basel, Switzerland Original application February 1, 1938, Serial No. 188,126. Divided and this application August 23, 1938, Serial No. 226,392. In Switzerland February 2, 1937 I 4 Claims. (Cl. 17$26) This application is divisional of my patent application Ser. No. 188,126, filed February 1, 1938.

The multi-pole connecting lamp caps and sockets of hitherto known construction'with more than two poles have the drawback that by maintaining the international standards for caps and sockets, the prescribed distance between the separate poles will usually not reach the limit which will allow realisation of the necessary creeping way of normal operating tension of 220 volts for example.

The purpose of the present invention is to eliminate this drawback.

The object of the present invention is an electric lamp connecting device comprising a multipole connecting lamp cap with at least three poles and a corresponding connecting socket for receiving the same, said cap having an outer contact formed on the cap body, at least one central contact on the end of the cap and an intermediate contact also arranged on the end of the cap, this device being characterised by that the said intermediate contact is so constructed, for instance in form of a funnel, as to define a conical contact surface having its apex in the central axis of the cap and its generator line, which preferably makes an angle of 45 with said axis, located between the two first mentioned contacts.

The connecting socket corresponding to such connecting cap has in addition to a contact surface on the part receiving the capand a central contact on its base, also on the face of the base turned towards the cap receiving part, a projecting contact adapted to make contact with the said intermediate contact lying recessed in the end of the cap, said projecting contact consisting for example of a funnel-like member or of a contact finger with its free end bent inwardly.

Due to the particular shape of the intermediate contacts of the cap and the socket, it is easily possible to realise the distance between these intermediate contacts and the corresponding adjacent contacts as is prescribed by the interna tional standards for such electrical appliances.

Two examples of embodiment of the electric lamp connecting device according to the invention are illustrated in the accompanying drawing.

Figure 1 is a part section through an electric lamp of known kind with a novel cap;

Figure 2 shows a modification of this cap;

Figure 3 is a plan view of a socket adapted to receive the cap of Figure 1 and Figures 4 and 5 are two vertical sections taken at right angles to one another of this socket.

In Figure 1 an electric lamp of known kindis shown, which is provided with the novel three pole cap; A is the glass envelope ofthis lamp 5 and B a three pole screw cap thereon, in which a moulding b of insulating material forming the end of the cap is mounted. This moulding has a projecting central part upon which a contact c shown as a projecting central contact is provided. On the end face of the moulding b is further provided an intermediate contact 0 Whose construction or arrangement is here of particular importance. As is shown by the drawing this contact 0 has the form of a funnel by which a conical surface is defined, the apex of which lies in the central axis of the cap B and the generator line of which is located between the central contact 0 and the outeror peripheral contact b formed by the screw thread part of the cap.

Advantageously the generator line of the said conical surface makes an angle of 45 with the central, axis of the cap B. The illustrated lamp has within its envelope A two glow filaments R and R which are connected to the contacts 0 and 0 respectively by leads r and r r is the common return lead connected to the screw thread part of the cap B. Obviously the lamp could have for example three glow filaments, when a four pole cap B (Figure 2 is necessary, which, as Figure 2 shows, has in a central recess an additional central contact 0 shown as a sunk contact.

A socket adapted to receive the cap according to Figure 1 is shown in Figures 3, 4 and 5. g' is the base of the socket, made of insulating material, united into a single whole with a threaded sleeve d for receiving the cap B (Figure 1) and forming one contact. In the centre of the base 9 is arranged a terminal to forming a central con tact; a terminal 22 electrically connected with the sleeve d is further provided in the base 9. In addition to these two terminals '0- and w yet another terminal marked a: is provided in the base 9, which on the face of the base turned towards the sleeve d is electrically connectedwith a contact member constructed as a finger h. This contact finger h which projects from the base 9 Within the sleeve d is bent inwardly at its free end and is designed, when the cap B (Figure 1) is screwed into the described socket, to make contact with the contact 0 of the cap B lying recessed in the end face of the cap.

The above mentioned contact member could also be formed as a counter-funnel to the funnellike intermediate contact of the cap B or B as indicated in Figure 5 by dotted lines.

What I claim is:

1. An electric lamp connecting device comprising a multi-pole connecting lamp cap with at least three poles and a corresponding connecting socket for receiving the same, said cap having a cap body, an outer contact formed on the periphery of said cap body, at least one central contact on the end of said cap b and a funnel-dike -p le connecting lam cap with at least tapered intermediate contact on the end of said cap body, so constructed as to define an upwardly enlarged conical contact cup having its apex in the axis of said cap body and its generator line located between said outer contact and said central contact.

2. An electric lamp connecting device having a lamp cap as set forth in claim 1, in which said generator line makes an angle of 45 with the axis of said cap body, '3'QAn'Velectric lamp connecting device having a niulti-pole connecting lamp cap with at least three poles as set forth in claim 1 and a corresponding connecting socket for receiving the smasam' connecting socket comprising an'insulating base, an external contact adapted to receive the lamp cap, at least one central contact on said base adapted to cooperate with the corresponding contact of the lamp cap, and an intermediate contact also arranged on said base, this intermediate contact being formed by a fingerrprojecting beyond said central contact and bent inwardly so as to be able to cooperate with the corresponding intermediate contact of the lamp cap.

4. An electric lamp connecting device having a three poles as set forth in claim 1 and a corresponding connecting socket for receiving the same, said connecting socket comprising an insulating base, an external contact adapted to receive the lamp cap, at least one central contact on said base adapted to cooperate with the corresponding contact of the lamp cap, and an intermediate contact also arranged on said base, this intermediate contact being formed by a funnel-like member projecting beyond said central contact and being adapted to cooperate with the corresponding intermediate contact of the lamp cap.

JOHANN BUSER. 

